As data rates increase for optical receivers in fiber optic communication systems, the active area of a photodetector must be reduced. Focusing the light exiting the fiber, particularly multi-mode fiber with a large core, to the photodetector becomes challenging. The lens used to focus the exit beam from the fiber has to produce a very small spot and achieve high precision in position. Monolithically forming a lens in the substrate of a photodetector, which results in high alignment accuracy owing to the use of wafer-level lithography, is not suitable for a photodetector whose substrate is opaque at the operating wavelength of interest.